The Chehalis Basin process includes fish recovery and flood protection projects in each community along the river.
One of the most significant projects is the North Rim Seawall project, including the western extension to protect Aberdeen and Hoquiam from flooding, sea level rise and future tsunamis. Today, thousands of homeowners in these communities cannot obtain federal flood insurance because their properties are exposed to these threats.
Without flood insurance, these homes and small business owners cannot get loans on their properties, they cannot refinance, and it is more difficult for them to sell. This resulted in a gigantic collective drop in land value for these owners and for the entire community in turn. This crisis for the communities of Twin Harbors devalued entire neighborhoods and drastically reduced revenues to fund basic services across the towns of Aberdeen and Hoquiam and the County of Grays Harbor.
The Chehalis River is only one contributor when catastrophic flooding occurs in Aberdeen and Hoquiam. These communities are at the end of the Chehalis River, where it empties into Grays Harbor, and then into the ocean. Water retention in the upper basin, retaining 65,000 acre feet of flood water above Pe Ell, reduces the peak of a 100-year flood in the main branch of the Chehalis River by half a foot as well. far downstream than Cosmopolis. This can have a positive impact by reducing the flood peak further downstream in Aberdeen, but there the influence of the tides becomes a more important factor than the level of the river.
The project that can provide direct benefits to Aberdeen and Hoquiam is the proposed North Shore Seawall project including its westward extension. We see this project as a critical part of the Chehalis Basin strategy, along with hundreds of kilometers of salmon habitat, water retention, limiting future growth in the floodplain, and local projects.
Already, every community in the basin has benefited from the engagement in the Chehalis basin process. In Gray Harbor alone, more than $ 32 million worth of projects protecting homes, schools and businesses were completed on time and on budget. In Grays Harbor County, these projects have been located in Montesano, Oakville on the Chehalis Reserve, Cosmopolis, Aberdeen and Hoquiam. The list goes on in Lewis and Southern Thurston counties as well.
Throughout the Chehalis Basin process, many ideas for flood protection and fish enhancement have been proposed. Sometimes it almost seems like there are as many ideas as there are people in the pool. But methodically using the best science with local contributions, these ideas were evaluated and either adopted, modified or shelved.
Recently, we saw a letter proposing an old idea: to create more flood storage in the floodplain along the river above Chehalis and Centralia. A hydrological analysis was carried out recently by the Chehalis Basin Office, showing that there is a grand total of 500 acres of unused floodplain along the main course of the Chehalis River, which means land at the bottom of the river. valley that are not already covered with river water. during a catastrophic flood. Adding 500 acres of new storage, when catastrophic flows hit 300,000 acre feet of water, is obviously not an idea that will add a measurable amount of flood protection for families and communities in the Chehalis Basin.
